My son’s power supply

Sometimes, my son suddenly falls asleep like a dead battery when he is playing with the tablet.

息子くん、タブレットで遊んでると、時々スイッチが切れたかのように突然寝る事があります。

校閲の内容

（修正前）
Sometimes, my son suddenly fall asleep as if the switched off while playing with the tablet.

fall → falls

as if the switched off → as if to be switched off もしくは like a dead battery など

when he playing → when he is (he’s) playing もしくは while playing など